You can go quickly to the question starting reading from 'Having said that'
The following are details on my specific needs

I'm on lubuntu oneiric and trying to create a desktop launcher to start / stop tomcat.
I'm experiencing problems which are explained in this thread I opened yesterday on lxde forum.

Basically the desktop launcher, which just executes the command/usr/local/tomcat6/bin/startup.sh
inside a lxterminal window works, but if I close the lxterminal window opened by the launcher and which executed the command .. then tomcat is just shut down.

I would like instead to close that window while having tomcat keeping running of course.
The window needs just to execute the command to start it and nothing else.

Searching inside the whoooole code run by the above command I finally found that the guilty is the following code:

So is there a way to start a job from a lxterminal window and have this job still running even after closing the lxterminal window which fired it?

To be clear:
I want to open a lxterminal window which executes a command (like top &), close this lxterminal window and still have the executed command running.

For those who read my details on the top page:
the strange is that if I open a lxterminal window, directly type/usr/local/tomcat6/bin/startup.sh
and then close that window .. then tomcat still runs.
Not from the desktop launcher which simply opens an lxterminal window and fire the same command and then it closes!

I think your (Tomcat-) processes are killed when the terminal window is closed because the shell, running in the terminal window, is the parent process of your Tomcat process.
so when a parent gets killed, all child processes are killed too.

If you don't want this to happen you could try launching your process like this: